Fish Nutrition

Fish research studies are the main activity at the Hagerman Fish Culture Experiment Station. Reducing the levels of fishmeal and fish oil in fish feeds is a high priority area of research and involves several approaches. Much effort is made to evaluate alternate protein sources to replace fishmeal. A long-term effort has also been made to develop strains of rainbow trout through selective breeding that exhibit high growth performance when fed all plant-protein feeds. Research to identify essential dietary compounds present in fishmeal and absent in plant proteins that must be supplemented to all plant protein feeds is also part of this research effort. Much of this research is conducted with USDA Agriculture Research Service partners. Similar efforts are made to lower the use of fish oil in feeds, yet maintain the healthful benefits of long-chain polyunsaturated omega-3 fatty acids in farmed fish products for human consumption. Increasing nutrient retention, meaning the use of nutrients in feeds to support fish growth, is another research thrust that has both economic and environmental benefits. Environmental impacts of fish farming are associated with loss of nutrients, mainly phosphorus, to the environment, so increasing phosphorus retention, for example, reduces the impacts of fish farms on the aquatic environment.

Many more topics are addressed in research studies at the Hagerman Station. These include studies associated with improving the survival of hatchery salmon and steelhead trout after release, understanding the basis of tolerance of some strains of fish to high water temperatures or other stressors, and developing novel ways to assess environmental stress in fish using non-lethal methods. CRITFC partners are associated with these efforts as well as with population genetics research on salmon and steelhead throughout the region.

Research involves fish rearing studies but also basic research into how the genome, cells, organs and fish respond to changes in the rearing environment, diet and pathogen challenge. Scientists use molecular techniques as well as proteomics and metabolomics to address these questions.